This invention concerns image pickup and observation equipment for endoscope with improved resolution.
Recently image pickup equipment using solid pickup element is being practically used for television cameras, endoscopes, etc.
The present endoscope uses a bundle of, for example, tens of thousands of optical fibers with the diameter of tens of microns called image guide and light guide as image transferring means and light transferring means, and a subject image formed at the end face of the image guide by the image-forming optical system provided in the end part of the endoscope can be observed through the eye lens optical system at the rear end of the said image guide which is extended to the operating side at hand.
In such a case, the resolution of the image observed depends on the number of optical fibers to form the image guide and the more the fibers, the better, but in the inserting member which is made small in diameter to reduce the pain of the patient, the number of fibers tends to be decreased, thus reducing the resolution. Also, the boundaries among the fibers are observed as dark meshes and especially when enlarged, the observation becomes difficult.
Even if the solid pickup element is used, the resolution is not sufficient with the number of picture elements which can be contained in the inserting member and accurate diagnosis cannot be made through the observation.
Even if it is used for the television camera, the number of picture elements of the solid pickup element tends to be insufficient, and for this reason, the conventional example publicized in the Nikkei Sangyo Newspaper of July 18, 1983 improves the resolution by vibrating the CCD (charge coupled device) by 1/2 pitch of the arrangement of the light receiving elements.
But since the above conventional example vibrates the CCD itself which is connected to many signal lines, the contact failure tends to occur in the long-term use. Also, it must be vibrated together with the electrodes, etc., the load increases, and therefore, the bimorph piezo-electric element to vibrate it also increases in size and the CCD including vibrating and driving system becomes bulky. For this reason, it is difficult to use it for the endoscope which has a narrow inserting member. Furthermore, it cannot be used for the endoscope which uses the image guide.